get_time_series

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds valuable behavioral context beyond those: the series is bounded to '0-100 values,' volume is included 'when available,' and rate-limit/quota failures should be reported as a plan limit issue. This meaningfully supplements the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, each earning its place: the core behavior, intended uses, exclusions with alternatives, and failure handling. The most important information is front-loaded, and there is no redundant restatement of the schema or annotations.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter historical data tool with a rich schema and an output schema, the description covers purpose, usage boundaries, alternatives, and edge behavior. Nothing an agent needs to select and invoke this tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides 100% parameter coverage with detailed descriptions for both keyword and source, including per-source keyword format rules and valid source values. The description adds only the high-level constraint 'one keyword and one source,' which the schema already implies. Baseline 3 is appropriate since the schema carries the parameter documentation burden.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states the exact resource and scope: 'Full historical series for one keyword and one source (0-100 values, plus volume when available).' It also names the intended use cases ('charting or custom math') and distinguishes itself from siblings by explicitly naming get_top_trends and get_growth.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage guidance is explicit and actionable: use for charting/custom math, not for live trending boards ('use get_top_trends'), and for most growth questions 'use get_growth.' It even includes rate-limit/quota handling behavior, leaving no ambiguity about when this tool is appropriate.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.